As mentioned in Table 4-10. Rules for modifying production workflows, a step cannot be deleted from a workflow when it is in use. It can only be disabled. However, you may want to change the process. Any changes to the process must be reflected in the workflow. This may require disabling existing steps and adding new steps.
Remove transitions to the existing workflow step you no longer want to use.
Add a new workflow step to the workflow.
Redirect the transitions to the new workflow step.